Probing anomalous quartic gauge-boson couplings via e⁺e^- → 4 fermions +γ

All lowest-order amplitudes for e⁺e^- → 4fγ are calculated including five anomalous quartic gauge-boson couplings that are allowed by electromagnetic gauge invariance and the custodial SU(2)_c symmetry. Three of these anomalous couplings correspond to the operators ℒ₀, ℒ_c, and ℒ_n that have been constrained by the LEP collaborations in WWγ production. The anomalous couplings are incorporated in the Monte Carlo generator RACOONWW¹. Moreover, for the processes e⁺e^- → 4fγ RACOONWW is improved upon including leading universal electroweak corrections such as initial-state radiation. The discussion of numerical results illustrates the size of the leading corrections as well as the impact of the anomalous quartic couplings for LEP2 energies and at 500 GeV.